// Copyright (c) 2010 Satoshi Nakamoto
// Copyright (c) 2009-2022 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#include <key_io.h>
#include <pubkey.h>
#include <rpc/protocol.h>
#include <rpc/request.h>
#include <rpc/server.h>
#include <rpc/util.h>
#include <script/descriptor.h>
#include <script/script.h>
#include <script/signingprovider.h>
#include <script/standard.h>
#include <tinyformat.h>
#include <univalue.h>
#include <util/check.h>
#include <util/strencodings.h>

#include <cstdint>
#include <memory>
#include <string>
#include <vector>

static RPCHelpMan validateaddress()
{
    return RPCHelpMan{
        "validateaddress",
        "\nReturn information about the given Dash address.\n",
        {
            {"address", RPCArg::Type::STR, RPCArg::Optional::NO, "The Dash address to validate"},
        },
        RPCResult{
            RPCResult::Type::OBJ, "", "",
            {
                {RPCResult::Type::BOOL, "isvalid", "If the address is valid or not"},
                {RPCResult::Type::STR, "address", /*optional=*/true, "The Dash address validated"},
                {RPCResult::Type::STR_HEX, "scriptPubKey", /*optional=*/true, "The hex-encoded scriptPubKey generated by the address"},
                {RPCResult::Type::BOOL, "isscript", /*optional=*/true, "If the key is a script"},
                {RPCResult::Type::STR, "error", /*optional=*/true, "Error message, if any"},
            }
        },
        RPCExamples{
            HelpExampleCli("validateaddress", "\"" + EXAMPLE_ADDRESS[0] + "\"") +
            HelpExampleRpc("validateaddress", "\"" + EXAMPLE_ADDRESS[0] + "\"")
        },
        [&](const RPCHelpMan& self, const JSONRPCRequest& request) -> UniValue
{
    std::string error_msg;
    CTxDestination dest = DecodeDestination(request.params[0].get_str(), error_msg);
    const bool isValid = IsValidDestination(dest);
    CHECK_NONFATAL(isValid == error_msg.empty());

    UniValue ret(UniValue::VOBJ);
    ret.pushKV("isvalid", isValid);
    if (isValid) {
        std::string currentAddress = EncodeDestination(dest);
        ret.pushKV("address", currentAddress);

        CScript scriptPubKey = GetScriptForDestination(dest);
        ret.pushKV("scriptPubKey", HexStr(scriptPubKey));

        UniValue detail = DescribeAddress(dest);
        ret.pushKVs(detail);
    } else {
        ret.pushKV("error", error_msg);
    }

    return ret;
},
    };
}

static RPCHelpMan createmultisig()
{
    return RPCHelpMan{"createmultisig",
                "\nCreates a multi-signature address with n signature of m keys required.\n"
                "It returns a json object with the address and redeemScript.\n",
                {
                    {"nrequired", RPCArg::Type::NUM, RPCArg::Optional::NO, "The number of required signatures out of the n keys."},
                    {"keys", RPCArg::Type::ARR, RPCArg::Optional::NO, "The hex-encoded public keys.",
                        {
                            {"key", RPCArg::Type::STR_HEX, RPCArg::Optional::OMITTED, "The hex-encoded public key"},
                        }},
                },
                RPCResult{
                    RPCResult::Type::OBJ, "", "",
                    {
                        {RPCResult::Type::STR, "address", "The value of the new multisig address."},
                        {RPCResult::Type::STR_HEX, "redeemScript", "The string value of the hex-encoded redemption script."},
                        {RPCResult::Type::STR, "descriptor", "The descriptor for this multisig."},
                    }
                },
                RPCExamples{
            "\nCreate a multisig address from 2 public keys\n"
            + HelpExampleCli("createmultisig", "2 \"[\\\"03789ed0bb717d88f7d321a368d905e7430207ebbd82bd342cf11ae157a7ace5fd\\\",\\\"03dbc6764b8884a92e871274b87583e6d5c2a58819473e17e107ef3f6aa5a61626\\\"]\"") +
            "\nAs a JSON-RPC call\n"
            + HelpExampleRpc("createmultisig", "2, [\"03789ed0bb717d88f7d321a368d905e7430207ebbd82bd342cf11ae157a7ace5fd\",\"03dbc6764b8884a92e871274b87583e6d5c2a58819473e17e107ef3f6aa5a61626\"]")
                },
        [&](const RPCHelpMan& self, const JSONRPCRequest& request) -> UniValue
{
    int required = request.params[0].getInt<int>();

    // Get the public keys
    const UniValue& keys = request.params[1].get_array();
    std::vector<CPubKey> pubkeys;
    for (unsigned int i = 0; i < keys.size(); ++i) {
        if (IsHex(keys[i].get_str()) && (keys[i].get_str().length() == 66 || keys[i].get_str().length() == 130)) {
            pubkeys.push_back(HexToPubKey(keys[i].get_str()));
        } else {
            throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, strprintf("Invalid public key: %s\n.", keys[i].get_str()));
        }
    }

    // Construct using pay-to-script-hash:
    FillableSigningProvider keystore;
    CScript inner;
    const CTxDestination dest = AddAndGetMultisigDestination(required, pubkeys, keystore, inner);

    // Make the descriptor
    std::unique_ptr<Descriptor> descriptor = InferDescriptor(GetScriptForDestination(dest), keystore);

    UniValue result(UniValue::VOBJ);
    result.pushKV("address", EncodeDestination(dest));
    result.pushKV("redeemScript", HexStr(inner));
    result.pushKV("descriptor", descriptor->ToString());

    return result;
},
    };
}

static RPCHelpMan getdescriptorinfo()
{
    const std::string EXAMPLE_DESCRIPTOR = "wpkh([d34db33f/84h/0h/0h]0279be667ef9dcbbac55a06295Ce870b07029Bfcdb2dce28d959f2815b16f81798)";

    return RPCHelpMan{"getdescriptorinfo",
        {"\nAnalyses a descriptor.\n"},
        {
            {"descriptor", RPCArg::Type::STR, RPCArg::Optional::NO, "The descriptor"},
        },
        RPCResult{
            RPCResult::Type::OBJ, "", "",
                {
                {RPCResult::Type::STR, "descriptor", "The descriptor in canonical form, without private keys"},
                {RPCResult::Type::STR, "checksum", "The checksum for the input descriptor"},
                {RPCResult::Type::BOOL, "isrange", "Whether the descriptor is ranged"},
                {RPCResult::Type::BOOL, "issolvable", "Whether the descriptor is solvable"},
                {RPCResult::Type::BOOL, "hasprivatekeys", "Whether the input descriptor contained at least one private key"},
                }
        },
        RPCExamples{
        "\nAnalyse a descriptor\n"
        +   HelpExampleCli("getdescriptorinfo", "\"" + EXAMPLE_DESCRIPTOR + "\"") +
            HelpExampleRpc("getdescriptorinfo", "\"" + EXAMPLE_DESCRIPTOR + "\"")

        },
    [&](const RPCHelpMan& self, const JSONRPCRequest& request) -> UniValue
{

    RPCTypeCheck(request.params, {UniValue::VSTR});

    FlatSigningProvider provider;
    std::string error;
    auto desc = Parse(request.params[0].get_str(), provider, error);
    if (!desc) {
        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, error);
    }

    UniValue result(UniValue::VOBJ);
    result.pushKV("descriptor", desc->ToString());
    result.pushKV("checksum", GetDescriptorChecksum(request.params[0].get_str()));
    result.pushKV("isrange", desc->IsRange());
    result.pushKV("issolvable", desc->IsSolvable());
    result.pushKV("hasprivatekeys", provider.keys.size() > 0);
    return result;
},
    };
}

static RPCHelpMan deriveaddresses()
{
    const std::string EXAMPLE_DESCRIPTOR = "wpkh([d34db33f/84h/0h/0h]xpub6DJ2dNUysrn5Vt36jH2KLBT2i1auw1tTSSomg8PhqNiUtx8QX2SvC9nrHu81fT41fvDUnhMjEzQgXnQjKEu3oaqMSzhSrHMxyyoEAmUHQbY/0/*)#cjjspncu";

    return RPCHelpMan{"deriveaddresses",
        "\nDerives one or more addresses corresponding to an output descriptor.\n"
        "Examples of output descriptors are:\n"
        "    pkh(<pubkey>)                        P2PKH outputs for the given pubkey\n"
        "    sh(multi(<n>,<pubkey>,<pubkey>,...)) P2SH-multisig outputs for the given threshold and pubkeys\n"
        "    raw(<hex script>)                    Outputs whose scriptPubKey equals the specified hex scripts\n"
        "\nIn the above, <pubkey> either refers to a fixed public key in hexadecimal notation, or to an xpub/xprv optionally followed by one\n"
        "or more path elements separated by \"/\", where \"h\" represents a hardened child key.\n"
        "For more information on output descriptors, see the documentation in the doc/descriptors.md file.\n",
            {
                {"descriptor", RPCArg::Type::STR, RPCArg::Optional::NO, "The descriptor"},
                {"range", RPCArg::Type::RANGE, RPCArg::Optional::OMITTED_NAMED_ARG, "If a ranged descriptor is used, this specifies the end or the range (in [begin,end] notation) to derive."},
            },
            RPCResult{
                RPCResult::Type::ARR, "", "",
                {
                    {RPCResult::Type::STR, "address", "the derived addresses"},
                }
            },
            RPCExamples{
        "\nFirst three receive addresses\n"
        + HelpExampleCli("deriveaddresses", "\"" + EXAMPLE_DESCRIPTOR + "\" \"[0,2]\"") +
          HelpExampleRpc("deriveaddresses", "\"" + EXAMPLE_DESCRIPTOR + "\", \"[0,2]\"")
            },
    [&](const RPCHelpMan& self, const JSONRPCRequest& request) -> UniValue
{

    RPCTypeCheck(request.params, {UniValue::VSTR, UniValueType()}); // Range argument is checked later
    const std::string desc_str = request.params[0].get_str();

    int64_t range_begin = 0;
    int64_t range_end = 0;

    if (request.params.size() >= 2 && !request.params[1].isNull()) {
        std::tie(range_begin, range_end) = ParseDescriptorRange(request.params[1]);
    }

    FlatSigningProvider key_provider;
    std::string error;
    auto desc = Parse(desc_str, key_provider, error, /* require_checksum = */ true);
    if (!desc) {
        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, error);
    }

    if (!desc->IsRange() && request.params.size() > 1) {
        throw JSONRPCError(RPC_INVALID_PARAMETER, "Range should not be specified for an un-ranged descriptor");
    }

    if (desc->IsRange() && request.params.size() == 1) {
        throw JSONRPCError(RPC_INVALID_PARAMETER, "Range must be specified for a ranged descriptor");
    }

    UniValue addresses(UniValue::VARR);

    for (int64_t i = range_begin; i <= range_end; ++i) {
        FlatSigningProvider provider;
        std::vector<CScript> scripts;
        if (!desc->Expand(i, key_provider, scripts, provider)) {
            throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Cannot derive script without private keys");
        }

        for (const CScript &script : scripts) {
            CTxDestination dest;
            if (!ExtractDestination(script, dest)) {
                throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Descriptor does not have a corresponding address");
            }

            addresses.push_back(EncodeDestination(dest));
        }
    }

    // This should not be possible, but an assert seems overkill:
    if (addresses.empty()) {
        throw JSONRPCError(RPC_MISC_ERROR, "Unexpected empty result");
    }

    return addresses;
},
    };
}

void RegisterOutputScriptRPCCommands(CRPCTable& t)
{
    static const CRPCCommand commands[]{
        {"util", &validateaddress},
        {"util", &createmultisig},
        {"util", &deriveaddresses},
        {"util", &getdescriptorinfo},
    };
    for (const auto& c : commands) {
        t.appendCommand(c.name, &c);
    }
}
